Door latch mechanism



May 27, 1958 w. L. CLIFTON, JR

DOOR LATCH MECHANISM Filed March 13, 1956 4 m N, m 4 3 0 w M W o 9 w 9 mm /A 7 w 1% m. M WW 1/ A. m u 4 m M 2 a: 4 or H Loknm 8% 6 4 4 8 2/ J 2 ml M k. H 2w 0 Memo ow.

United States PatentO DOOR LATCH MECHANISM Walter Leonard Clifton, In, Atlanta, Ga., assignor to American Art Metals Company, Atlanta, Ga., a corporation of Delaware Application March 13, 1956, Serial No. 571,173 1 Claim. (Cl. 292-21) The invention relates to latches of the type used on exit doors, usually referred to as panic latches, and more particularly to a dogging-clown construction for holding s'uch latches in an open position.

It is an object of this invention to provide a latching device including an improved construction for doggingdown the latch to hold it in an open or unlatched position.

Still another object of the invention is to provide a dogging-down mechanism for use with panic latches and the like in which the dogging-down mechanism is effective to hold the latch open only when the operating mechanism for the latch is moved to a predetermined position.

It is still a further object of this invention to provide a dogging-down mechanism for use with panic latches and the like in which the doggingdown mechanism is operable only at the discretion of the operator and is not automatically movable into dogging-down position as in the case of some mechanisms for this purpose.

It is still a further object of this invention to provide a dogging-down mechanism for use with panic latches and the like in which the dogging-down construction includes a member which is axially movable to effect a dogging-down operation, with the parts being so arranged that the axially movable member is limited to a certain predetermined range of movement and cannot be backed oil.

In achievement of these objectives, there is provided in accordance with an embodiment of this invention a dogging-down mechanism for use with panic latches and the like in which the lever member which operates the panic latch lifting rods is pivotally movable between a pair of spaced bracket arms. The pivotably movable ever member has a threaded bore in which a set screw member is movable. The bracket arm on one side of the movable lever member has a passage or bore to receive a tool which engages and turns the set screw, while the opposite bracket arm has a bore which receives an end of the set screw, to thereby hold the operating lever in a position which holds the latch members in an unlatched position. The dogging-down operation is performed by pivotally moving the operating lever to the position in which the latch members operated by the lever are in unlatched position. In this same position of the lever, the set screw carried by the lever is aligned with the bores of the fixed bracket members so that a tool may be inserted through the bore of one bracket member to engage and turn the set screw and so that a reduced opposite end portion of the set screw moves into the bore of the opposite bracket member. The end opening of the bore in the lever member which receives the set screw is upset to prevent the set screw from being backed off out of the bore in the lever. The passage in the bracket arm through which the operating tool is inserted is of smaller diameter than the bore in the lever and smaller than the diameter of the set screw to further prevent movement of the set screw out of the bore in the lever.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a view in vertical section showing details of 2,836,451 Patented May 27, 1958 ice 2 the panicdoor and of the panic latch mechanism embodying the invention;

Fig. 2 is an enlarged view in vertical section showing the operating lever of the panic latch mechanism; and

Fig. 3 is a view in vertical section along line 33 of Fig. 2 showing details of the construction of the doggingdown device.

Referring now to the drawing, and more particularly to Fig. 1, there is shown a door frame It} and a threshold 12 respectively having latch-accommodating slots 14 and 16. A door generally indicated at 18 is provided at its free edge with a hollow casing 20 for receiving the latches and their actuating mechanism. At the upper end of casing 20 a latch generally indicated at 22 is pivotally supported on pin 24 and is biased by spring 26 in such manner that latch 22 normally tends to move upwardly through slot 14 to engage door frame 10 in latching relation. Latch 22 is in the shape of a bell crank and is provided with an arm 28 which extends downwardly from the pivotal axis 24 as best seen in Fig. 1. A latch 30 similar to the latch 22 just described is provided at the lower end of casing 20. The lower latch member 36 is biased by a spring 31 into latching engagement with threshold 12 through the aperture 16 of the threshold and is provided with an arm 32 which extends upwardly from the pivotal axis 'of latch 30.

The operating mechanism for moving the latches 22 and 30 to unlatched position includes an operating lever generally indicated at 34 which is pivotally supported by an aperture 46 in a C-shaped yoke member 48 disposed on the interior of casing 20. Rod members 50 and 52 are rigidly attached to the upper and lower ends, respectively, of yoke member 48. At the upper end of rod member 50 is rigidly attached a drag angle 54 and a similardrag angle 56 is rigidly attached to the lower end of rod member 52. Rods 50 and 52 are guided for vertical movement within casing 20 by apertured bracket members 53, 60, 62 and 64 carried by casing 20. A spring 66 disposed between bracket 60 and the upper end of yoke 48, and a second spring 68 disposed between bracket 64 and the upper end of angle member 56 cooperate with the natural weight of the assembly to normally bias yoke 48 and the attached rod and angle members in a downward or latching direction.

Mounted within casing 20 below latch 22 is a bell crank lever generally indicated at 70 including an arm 72 which extends into a slot 74 of upper angle member 54; Bell crank 70' also includes an arm 76 which is movable into engagement with the downwardly extend ing arm 28 of latch member 22. In a similar manner,

a' bell crank lever generally indicated at 78 is supported at the lower end of casing 20 and includes an arm 80 member 54 atthe upper end of the casing to rotate bell cr'ankmember 70 in a counterclockwise direction with respect t'o' the view shown in Fig. 1 and causes angle member 56'at the lower end of the casing 20 to rotate of set screw 88 when the set screw spect to the view shown-in Fig. -1. The rotation of the respective bell crank members 70 and 78 causes the respective latch members 22 and 30 to be pivotally moved in a clockwiseand a -counterclockisedirection,'respectively, and thus to be retracted to unlatched position."

In accordance with the present invention, a doggingdown mechanism is provided for maintaining. latch members 22 and 30 in a retracted or unlatched position when desired. For this purpose,- actuating arm 44 of operating lever 34 is provided with a threaded bore 86 -(see Fig. 3) which extends transversely in a horizontal direction through arm 44 in a portion ofarm 44 which lies between bracket portions 38 and 40. A set screw 88 is positioned in. threaded engagement with threaded bore 86. Screw 88 is provided at one of its ends with a hexagonal-shaped'recess 89 which'receives; a suitable operating toolto permit rotation of set screw 88 within an end portion 92. of reduced diameter at its opposite end. Bracket portion 38 .on the other side .of actuating arm 44 has ,a bore which receives reduced. endportion 92 is aligned with passages 90.and 94. 7 Under normal conditions, the weight of the O-shaped yoke member 48 of theattachedrod'members 50 and 52, and of angle members 54 and 56, together with the force of biasing springs 66 and 68, normally urges the entire latching assembly ,ina downward direction to. the

position shown in Fig. 1,. permitting latch members 22 and 38 to bebiased by their respective spring members 26, 31- into latching engagement with door frame and threshold 12, respectively. In this downward position the set screw. 7

It can be seen from the foregoing that there is pro-- of yoke 4S and of the members attached thereto, op-

erating lever 34 is maintained in theposition shown in passage. 90 of bracket portion and also out of align-. ment with bore or passage 94 of bracket portion-38;

When it is desired to hold latch members 22 and 30 in their Iunlatched position, operating lever, 34 is pushed toward the surface of door 18, in a counterclockwise direction with respect to the view shown in Fig. .1 to thereby raise yoke 48 and the attached rods and angle members to move latch members 22 and 30 to unlatched position.

In so doing, the threaded bore 86 and set screw 88 car- .riedby operating arme44 are moved into horizontal alignment withrecess or bore 94 in bracket portion 38 and also into alignment with recess'90 in bracket portion 40.. A suitable tool or wrench may then. be inserted diameter than the set screw, et of suflicientdiameter to permit easy insertion of the operating tool which engages vided in accordance with this invention a doggingdown construction particularly useful .with' panic latches and the like which permits the panic latch assembly ,to be maintained in unlatched -position.. The doggingdown construction hereinbefore described is such as to require that the latching assembly be moved to unlatched position before the set screw member which provides the dogging-down action can be moved into dogging 'down position. This prevents any possibility of -do'g- "ging-down the latching assembly in a latched position. 7

Furthermore; the set screw dogging-down construction hereinbefore described is operable to perform, its dog-' ging-down function only when intentionallymoved into dogging-downposition by operation of a suitable tool and does not automatically move into dogging-down position as in the caseof some devices of this general;

character. 7

'A fu'rther advantage of the construction is the fact that embodiment of'the invention, it will be obviousto those skilled in the art thatvarious' changes and modifications maybe made therein without departing, from the invention,--and.therefore it is aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention. What is claimed is: r

A dogging-down construction for use with'ajlatch mounted on a panic door or the like comprising a support bracket member fixedly mounted onsaid door, said bracket member including a pair of transversely spaced bracket portions and a transversely extending shaft, a lever member supported on said shaft for pivotal movement between said" bracket portions, means operatively con.-

necting a portion of said lever member remote fromsaid shaft to said latch, said lever member being movable to through passage 90 and intoengagement with hexagonal 8 socket 89. Set screw 88 may be turned to engage reduced end portion 92 of the set screw with the bore or socket 94 inbracket portion 38. The engagement of the set screw with bore or socket94 maintains operating lever- 34 and operating arm 44 in the position shown in 'Fig'. 2 and also maintains latch members 22 ,and 30 in screw 88, thereby preventing a backing ofi inovement of the set screw beyond the end opening of the .bore 86 which faces bracket portion 40. This upsettingrof the end opening of threaded bore, 86 as just described in no way'restricts, the insertion of the operating. tool into engagernent with hexagonal recess 90 of the set screw the hexagonal. recess. is of. substantially. smaller diameter than the. 'outerfdiameterofthe set screw As a further bracket was; j fmat o sqmsw at sm lle fjwith said'reducedrec ess for receiving an operating tool engageable with said set screw, said threaded bore of said l'ever being alignedwith both said other bore andsaid 'm'eansof preventing backing oft ofthe set sCrewQb re Tan actuatedposition to move the latch to :an unlatched position, said lever member having a threaded bore, said bore being interposed between said shaft and said remote portion and'said bore lying between said bracket portions 'at all positions of said lever member, a set screwthreadedly adjustable in said here and having a reduced end portion projecting Jaxially thereof, one of said bracket portions having a recess of reduced diameter forreceiving thereduced end portion only of said set screw, the other of said bracket portions having a' passage therethru. of

smaller diameter than said set screw and axially aligned passage to' define an elongated aperture extending through said other bracket when said lever-is in said actuated .portion and said lever and terminating interiorly of said one bracket portion when'said lever. is in said actuated ,position,said setscrew beingengageable by an operating tool for threaded adjustment into said recess to. hold said lever insaid actuated position and said .set screwbeing 'entirely concealed at all times.

References Cited in the file of this patent i "UNITED STATES PATENTS Howerton May 13, 1913 1,357,007 5 Smith -s Oct.26, 1920 1,646,990 Bolles Oct. 25, 1927 2,186,678 Johnston Jan.:9, 1940 2,505,190 I Kulbersh Apr. 25, .1950 

